Gambit-list Juin 2007

gambit-list@iro.umontreal.ca

19 participants
20 discussions

Termite and Windows
by Nathan Wong 14 Jui '07

14 Jui '07

Thanks for the quick response. When I use Cygwin, "./configure" seems to run fine, but "make boostrap" fails. It says "gcc: no input files". I'm using mingw32-make.exe. - Nathan

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Gambit's Linking Model
by Guillaume Cartier 14 Jui '07

14 Jui '07

Hi everyone, Unfortunately, I think I have stumbled upon a major problem for my project with the linking model of Gambit / Scheme's lack of specification for linking code. For my applications I absolutly need the ability to be able to load code selectively. If I understand correctly, the Gambit linking model is that all classes compiled into a .exe are loaded upon launching the .exe so that cannot do for me. The only alternative I see is the use of .o1 loadable code but is it reasonable to dynamically load like 1000+ .o1 files? Wouldn't launching incur a huge penalty in speed / space vs a selfcontained .exe as every .o1 is a full fleged dynamic library? Also, with this approach, distributing to my clients a folder containing 1000 .o1 files is everything but nice. I could zip them together a bit like interpreted languages like Python do but then I don't think Windows or Gambit or ... can load .o1 files from a zip directly so I'd have to unzip them to a temp folder which is again not very tempting. Any help / thoughts really appreciated. This is criticaly for my using Gambit for my project. Thanks, Guillaume

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gambit cgi error 11
by |/|/ Bendick 13 Jui '07

13 Jui '07

Hi, I'm trying to use gambit 4.0b22 for CGI but am having a problem. A simple script: #!/usr/local/Gambit-C/current/bin/gsi-script (define (main . args) (display "Content-type: text/html\n\nhi\n\n") (force-output (current-output-port)) 0) But I get a "500 - Internal Server Error" every time I try to hit the page. The web server (lighttpd-1.4.15) tells me the script is exiting with a return value of 11 which the gambit manual doesn't document. The script runs fine from command line. If I just throw: #!/bin/sh echo "Content-type: text/html" echo "" echo "hi"; into the file, it works correctly so it doesn't look like a permission/configuration/whatever error with the web server. Any ideas on code 11? -- |/|/ Bendick

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Termite and Windows
by Nathan Wong 13 Jui '07

13 Jui '07

Hi, Has anyone successfully gotten Termite running on Windows? If so, would it be possible to provide instructions for compiling or even the libraries/binaries themselves? Thanks, Nathan Wong

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Debugging macros
by Guillaume Cartier 09 Jui '07

09 Jui '07

If an error occurs during the expansion of a macro, Gambit doesn't start a new repl to enable me to debug the code. Is there a way to enable this? It would be really helpfull for me as some of my macros are really complex. For instance: Gambit Version 4.0 beta 22 > (define-macro (foo) (car 1)) > (foo) *** ERROR -- (Argument 1) PAIR expected (car 1) > Thanks, Guillaume

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Re: [gambit-list] [erlang-questions] Scheme on the Erlang VM
by Marc Feeley 04 Jui '07

04 Jui '07

On 4-Jun-07, at 3:03 PM, Luke Gorrie wrote: > "Philip Robinson" <chlorophil(a)gmail.com> writes: > >> On 6/2/07, Joel Reymont <joelr1(a)gmail.com> wrote: >>> >>> What about Scheme on the Erlang VM? >> >> I would *love* a Scheme/Lisp on the Erlang VM. > > For a toy starting point see 'lersp' in the Jungerl. > > The most fun bit of writing a Scheme interpreter IMO is to write > things like lersp/priv/core-macs.ler i.e. to implement 'let', 'case', > 'if', etc from a small kernel. > > Core Erlang would probably make a nice target language for a Scheme > dialect. I just couldn't resist the challenge and wrote a prototype Scheme to Erlang compiler (named Stoe of course) that is based on the front-end of the Gambit-C Scheme compiler. The code is attached below. It is just a prototype and it only handles a subset of Scheme, but it could be the starting point for a more complete Scheme to Erlang compiler. Stoe supports some of the Termite language and mutation of local variables. Here's a sample usage: % cat test.scm (define (fib n) (if (< n 2) 1 (+ (fib (- n 1)) (fib (- n 2))))) (define (fact n) (if (< n 2) 1 (* n (fact (- n 1))))) (define (iota n) (iota-2 n '())) (define (iota-2 i lst) (if (> i 0) (iota-2 (- i 1) (cons i lst)) lst)) (define (tally) (let ((sum 0)) (lambda (x) (set! sum (+ sum x)) sum))) (define (process n dest) (lambda () (! dest (map (?) (iota n))))) (define (main) (let ((a (spawn (process 10 (self)))) (b (spawn (process 10 (self)))) (t1 (tally)) (t2 (tally))) (! a fib) (! b fact) (map t1 (?)) (map t2 (?)) (list (t1 0) (t2 0)))) % gsc -i stoe.scm test.scm % cat test.erl -module(test). -export([fib/1,fact/1,iota/1,iota@2d@2/2,tally/0,process/2,main/0]). fib(N) -> if (N < 2) -> 1; true -> (fib((N - 1)) + fib((N - 2))) end. fact(N) -> if (N < 2) -> 1; true -> (N * fact((N - 1))) end. iota(N) -> iota@2d@2(N,[]). iota@2d@2(I,Lst) -> if (I > 0) -> iota@2d@2((I - 1),[I|Lst]); true -> Lst end. tally() -> Sum = schemelib:box(0), fun (X) -> schemelib:setbox(Sum,(schemelib:unbox(Sum) + X)), schemelib:unbox(Sum) end. process(N,Dest) -> fun () -> (Dest ! lists:map(receive Tmp_1 -> Tmp_1 end,iota(N))) end. main() -> {T2,T1,B,A} = {tally(),tally(),spawn(process(10,self())),spawn (process(10,self()))}, (A ! fun fib/1), (B ! fun fact/1), lists:map(T1,receive Tmp_2 -> Tmp_2 end), lists:map(T2,receive Tmp_3 -> Tmp_3 end), [T1(0),T2(0)]. % erl Eshell V5.5.4 (abort with ^G) 1> c(schemelib.erl). {ok,schemelib} 2> c(test.erl). {ok,test} 3> test:main(). [4037913,231] Marc

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Gambit's Debugger
by Guillaume Cartier 04 Jui '07

04 Jui '07

I added (display-environment-set! #t) to my gambcext.scm thinking it would automate the tedious task of always typing ,e after changing frames in the debugger. It does show the environment after frame changes but seems buggy as what gets displayed is different (and not correct) from what I get if I do an explicit ,e. Is it something I don't understand or a bug? Guillaume

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ffi and u8vectors, s8vectors, ...
by Andreas Huber 03 Jui '07

03 Jui '07

Hi, I've been playing around with Gambit's foreign function interface today, and the big stumbling block i've hit is that I cannot easily pass u8vectors to native code, i.e. u8vector is not compatible with (pointer void) or (pointer unsigned-int8). Is there a chance this might be changed in the future? I would _not_ want the address of a copy of the bytevector's contents to be passed to c-code but a pointer to the original u8vector's storage location instead. I am guaranteed that GC will not move my memory for the duration of this foreign call, am I not? (unless of course, scheme is reentered from within that native call, in which case all bets are off, right?) If there's an easier way of accomplishing this already supported I would of course love to hear it. Best regards, Andreas

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Bill Clementson's Blog: Parallel Map Beer Song in Erlang
by Bradley Lucier 01 Jui '07

01 Jui '07

How does one do parmap, found in the following blog entry by Bill Clementson, in Termite? http://bc.tech.coop/blog/070601.html It appears a similar implementation would use list comprehensions; so a related question is whether anyone is interesting in snowing srfi-42: http://srfi.schemers.org/srfi-42/srfi-42.html Brad PS: I hereby claim the first use of "to show" as a transitive verb in English!

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Flushing not done ?
by Adrien Pierard 31 Mai '07

31 Mai '07

Hello ! I've been writing some code today, dumping data in files on the hard disk. I knew that gambit, and many (if not all) languages buffers data before enventually writing it to the disk. What puzzled me today, is that it actually never got written ! Here is the code : (let ((o (open-output-file "/tmp/flushed-data"))) (display "whirl" o) (display "\n" o)) I thought that when the gambit process cleanly finishes, it would flush the port, though it didn't. I had to append a (close-output-port o) in order to have my data dumped. So, is that an undocumented feature, do I have to do the display in the IO monad ? Or is it just fully compliant with the "do what you want with the little constraint in the RnRS" ? This behaviours happens as well with interpreted code as woth compiled code. Isn't the OS (or the libc behind gambit) supposed to flush when the process terminates ? Should I stick to CALL-WITH-OUPUT-FILE or always close ports ? Adrien -- " am not a Church numeral; I am a free variable!" (The Scheme Underground)

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Gambit-list Juin 2007